Biometric identification systems, like fingerprints and eye scans, are old hat. Try this on –or in– for size: a PayPal executive who works with engineers and developers to find and test new technologies, now says that embeddable, injectable, and ingestible devices are the next wave in identification for mobile payments and other sensitive online interactions.

In a presentation called Kill all Passwords that he’s recently started giving at various tech conferences in the U.S. and Europe, PayPal’s global head of developer evangelism Jonathan Leblanc argued that technology has taken a huge leap forward to “true integration with the human body.”

Leblanc said that identification of people will shift from “antiquated” external body methods like fingerprints, toward internal body functions like heartbeat and vein recognition, where embedded and ingestible devices will allow “natural body identification.”

These devices include brain implants and attachable computers, which “put users in charge of their own security,” he said. Ingestible devices could be powered by stomach acid, which will run their batteries, he added.